On the glass substrate of a display, there is provided with a thin film transistor (TFT) array which generally consists of several pixel circuits arranged in rows and columns. Each pixel is provided with a corresponding pixel circuit which provides a corresponding pixel voltage to thereby control display of each pixel.
The existing pixel circuit is typically of a 1T1C structure, i.e. formed on the basis of a transistor (e.g. a TFT) plus a capacitor. Switching-on and switching-off for the transistor T is controlled by a gate signal (Gate) provided by the gate driver, and the capacitor C is charged by a source drive controller based on a data signal (Data), thereby reaching a certain pixel voltage. The pixel voltage may be used to drive liquid crystal for the corresponding pixel.
To achieve different grayscales, the pixel circuit needs to provide pixel voltages of different magnitudes, i.e. grayscale voltages. However, different grayscale voltages are usually provided by the Gamma circuit and the source driver of the TFT array. Specifically, the Gamma circuit needs to provide a plurality of fixed node voltages, which then will be divided finely by multiple Gamma resistors inside the source driver to obtain a plurality of digital voltage values (i.e. Gamma reference voltages) such as a 6-bit voltage value. Then they are subjected to digital-to-analog conversion and applied to the capacitor of the corresponding pixel circuit to generate a corresponding pixel voltage.
The biggest problem existing in driving such pixel circuit is leading to relatively large logic power consumption and a relatively complex driving circuit for TFT array. Furthermore, since the grayscale voltages for the RGB sub-pixels must be shared, to realize an 8-bit voltage value, the cost in control is higher, the algorithm is complicated, and the debugging cycle is long.